A troy ounce is a unit of weight commonly used to measure precious metals like gold, silver, and platinum. It is part of the troy weight system, which dates back to the Middle Ages and was originally used in the trading of goods. One troy ounce is equivalent to approximately 31.1035 grams. Unlike the more common avoirdupois ounce, which is used for everyday items, the troy ounce is specifically designed for precious metals. This distinction is important for investors and traders in the gold and silver markets, as it ensures accurate pricing and valuation of these commodities.